Pencil sharpener



Aug. 7, 1951 H. H. EWALD PENCIL SHARPENER Filed May 7, 1949 Ill/Ill,

INVENTOR.

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BYHOW/IED H. 51/440 ffu 74m,

Patented Aug. 7, 1951 UNITED STATES PATENT OFFICE PENCIL SHARPENER Howard H. Ewald, Los Angeles, Calif.

Application May 7, 1949, Serial No. 91,973

I 15 Claims.

This invention relates to pencil sharpeners, and particularly to sharpeners adapted to be used by draftsmen.

It is highly desirable that pencils for such purposes be maintained sharply pointed, since, otherwise, broad, indefinite lines result. Accordingly, frequent sharpening of the pencil is essential; and this has been done inthe past by the aid of fine sandpaper or, emery cloth, or, by pencil Sharpeners. Such pencil Sharpeners, however, were either too expensive, or else they often caused the point to be broken off in the process of sharpening the pencil.

It is one of the objects of this invention to provide a simple and inexpensive sharpener that can be used without danger of breaking the point.

It is another object of this invention to provide a simple pencil sharpener that permits adjustment of the knives orcutting members to the position of the pencil; thereby preventing the creation of a bending force on the point, tending t fracture it.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will nowbe described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is an elevation of a pencil sharpener incorporating the invention;

Fig. 2 is an enlarged fragmentary vertical section of the pencil. sharpener, illustrating the sharpening elements;

Fig. 3 is a sectional view, taken along a plane corresponding to line, 3-3 of Fig. 2;

Fig. 4 is an exploded view of the elements shown in Fig. 2; and.

Fig. 5 is a sectional view, taken along a plane corresponding to line 5-5 of Fig. 4.

In this instance, the pencil sharpener includes four substantially, identical sharpening elements or cutters I.

These cutters have a non-circular section, and are shown in the present instance as square, thus providing, for each cutter, a number of longitudinally extending cutting edges 2. These cutters are held so that the active edges thereof converge to a point whereby relative rotation between these cutters and a pencil will produce a sharpened point corresponding to the convergence of the active cutting edges illustrated in Fig. 3.

In a manner to be hereinafter described, it is a simple matter to change the cutting edges 2 so as to render active any of the edges of the individual cutting elements I.

The lower converging ends of the elements 2 are accommodated in a recess 3 formed in a base 4. This base 4 forms a part of a receptacle 5. The ends of the cutters rest upon a support, such as a ball 6, which is received in the recess 3. The upper portion of the recess 3 has an interrupted circular section which has adiameter substantially the same as the ball 8. The lower portion of the recess 3 is square, and forms the relatively shallow shoulders I upon which the ball 6 rests.

The receptacle 5 includes, in this instance, a series of four arms 8, which rise from the base 4 and are separated by slots. The arms 4 serve as spring fingers for detachably gripping other elements, as will be hereinafter described.

Thus, each of the arms 8 has a thickened upper portion 9, having a tapered surface I0 forming parts of a conical surface that diverges downwardly. This tapered surface II], at its lower end, serves to define a horizontal shoulder II formed on each arm. Disposed on the shoulder II is a restraining means for the upper or diverging ends of the cutting elements I. This restraining means I2 is shown, in the present instance, as of disclike configuration, having radially extending projections I3 which are received in slots between the adjacent arms 8. This disc-like element has appropriate square apertures for the accommodation of the upper ends of the cutting elements I. The restraining means I2 is frictionally held on the shoulder II by the resilience of arms 8. Due to the non-circular section of elements I, they are restrained against rotation relative to the receptacle 5.

It is preferable to arrange the cutting edges of the elements I so that not more than three can cut at one time. The fourth edge, that formed at the upper left-hand corner, does not cut, but merely forms a guide for the pencil. Furthermore, the angular spacing of the edges is unequal. The restriction to three cutting edges and unequal angles result in smooth cutting.

In order to restrict movement of the elements I upwardly from the recess 3, use is made of a conical washer I4. This conical washer has an outer edge which is frictionally gripped by the sloping surface It. Its inner edge overlies the upper ends of the elements I.

In order to change the cutting edges, the washer M and the restraining means i2 are first removed from between the upper ends of the arms 3; then the cutting elements i may be rearranged, and the restraining means i2 and washer M may be reinserted.

The assembly thus far described is adapted to be coupled to a barrel !5 which serves as a guide for the pencil to be sharpened. This barrel is may be appropriately provided with bands of knurling it to serve as a hand grip. The pencil may be inserted downwardly into thcbarrel so that the point of the pencil projects inwardly be" tween the cutting edges 2.

Provisions are made for so coupling the sharpener assembly and the barrel l5 as to permit some universal movement between the barrel i5 and the sharpening elements In this way, during the course of rotation of the pencil in the barrel 1 there is no material bending strain placed on the point, and the pencil may be sharpened without danger of breaking the point.

In order to accomplish this result, use is made of a coupling member IT. The coupling member has internal threads 18 cooperating with the external threads l9 provided at the lower end of the barrel 5%. The coupler also has an inwardly extending flange 2U which has an internal spherical surface 2 l.

spherical surface 22 formed on the exterior of the arms 8 and below the enlarged projections 9. These surfaces form a universal joint. The aperture 28, formed through the flange 28, is large enough to provide substantial clearance between the arms 8 and the coupling member W.

The coupling member II, when it is threaded into place against the shoulder 2'4 of the barrel 1%, does not clamp the sharpener assembly against the barrel; instead, there is sumcient looseness to permit easy relative movement be tween the two spherical surfaces. This is indicated by the alternate positions of the sharpener assembly, shown by dotted lines bearing reference characters 25 and 26 in the lower portion of Fig. 1.

Provisions are also made to prevent relative rotation between the barrel [5 and the sharpener assembly. For this purpose, the lower end of the barrel i5 is provided with a plurality of angularly spaced projections 21. These projections extend loosely into the slots between the arms 8, as shown most clearly in Fig. 2. Suiiicient clearance is provided to permit automatic alignment of the sharpener elements with the pencil point when the instrument is used.

When it is desired to sharpen a pencil, it is merely necessary to hold the barrel IS in one hand and to insert a pencil in the barrel i5 and rotate it. The point of the pencil will be formed by the convergent longitudinal cutting edges 2. Due to the freedom of universal motion of the sharpener assembly, a fine and long tapering point will be produced without danger of breaking. The taper is determined by the convergence of the cutting elements I. The slots between the arms 8 permit egress of the cuttings.

The inventor claims:

1. In a pencil sharpener: a pencil receiver; one or more sharpening members; and a support for the members, and carried by the receiver; said receiver and support having cooperating surfaces, one of said surfaces being convex and the other being concave, in which the convex surface is seated, said surfaces providing a limited universal movement between said receiver and support.

This internal spherical sur .face cooperates with the external interrupted 2. In a pencil sharpener: a barrel; a plurality of sharpening members having converging cutting edges; a support for the members, providing a rest for one end of each of the members, said end corresponding to the point of the pencil; and means joining the barrel and the support; said means and the support having cooperating surfaces, one of said surfaces being convex and the other being concave, in which the convex surface is seated to permit limited universal movement between them.

3. In a pencil sharpener: a barrel open at both ends serving as a receiver and guide for a pencil;

a sharpening assembly including sharpening elements; and a detachable coupling between one end of the barrel and the assembly; said coupling and the assembly having cooperating surfaces, one of said surfaces being convex and the other being concave, in which the convex surface is seated.

4. In a pencil sharpener: a barrel open at both ends serving as a receiver and guide for a pencil; a sharpening assembly including sharpening elements; and a coupling detachably joined to one end of the barrel; said coupling having a spherical seat aligned with the barrel; said assembly having a spherical surface nested in said seat; said barrel having means limiting relative movement of the assembly with respect to the barrel.

5. In a pencil sharpener: a barrel open at both ends serving as a receiver and guide for a pencil; a sharpening assembly including sharpening elements; and a coupling threaded on the barrel; said coupling having a spherical seat aligned with the barrel; said assembly having a flange with a sperical surface nested in said seat, and having a portion extending through the seat and away from the barrel; said assembly and the barrel having interengaging parts limiting relative movement of the assembly with respect to the barrel.

6. In a pencil sharpener: a barrel open at both ends serving as a receiver and guide for a pencil; a sharpening assembly including sharpening elements; and a coupling threaded on the barrel; said coupling having a spherical seat aligned with the barrel; said assembly having a flange with a spherical surface nested in said seat, and having a portion extending through the seat and away from the barrel; the contiguous ends of the barrel and the assembly having interengaging projections and slots to limit relative rotation between the barrel and the assembly and inward movement of the assembly.

'7. In a pencil sharpener: a plurality of sharpening elements having converging cutting edges; a receptacle for the inwardly directed ends of the elements; said receptacle having spring arms extending around the outwardly directed ends of the elements; a member received by the arms and having apertures for holding the said outwardly directed'ends; and means frictionally held by the arms for restraining said outwardly directed ends.

8. In a pencil sharpener: a plurality of sharpening elements having converging cutting edges; a receptacle for the inwardly directed ends of the elements; said receptacle having spring arms extending around the outwardly directed ends of the elements; said arms having inwardly directed ends; and a member having projections fitting between arms of the receptacle and frictionally gripped thereby; said member having apertures for holding the said outwardly directed ends.

9. In a pencil sharpener: a plurality of sharpening elements having converging cutting edges; a receptacle for the inwardly directed ends of the elements; said receptacle having spring arms extending around the outwardly directed ends of the elements; said arms having inwardly directed ends; a member having projections fitting between arms of the receptacle and frictionally gripped thereby; said member having. apertures for holding the said outwardly directed ends; and a conical washer having its outer edge held frictionally by the inwardly directed ends of the arms and resting on the outwardly directed ends of the sharpening elements.

10. In a pencil sharpener: a sharpening element of uniform cross section; said element having a plurality of longitudinally extending cutting edges; means confining the element at one end thereof; and means restraining the other ends of the element in such manner that only one edge of the element is effective and converges to the confining means; said element being removable and replaceable with respect to the confining and restraining means to bring other edges into effective position.

11. In a pencil sharpener: a plurality of sharpening elements having converging cutting edges; a receptacle for the inwardly directed ends of the elements; said receptacle having spring arms extending around the outwardly directed ends of the elements; a member received by the arms and having apertures for holding the said outwardly directed ends; means frictionally held by the arms for restraining said outwardly directed ends; a barrel for receiving and guiding a pencil; said receptacle having an external spherical surface; and a coupling member having an interior spherical surface cooperating with said external surface and carried by the barrel.

12. In a pencil sharpener: a plurality of sharpening elements having converging cutting edges; a receptacle for the inwardly directed ends of the elements; said receptacle having spring arms extending around the outwardly directed ends of the elements; a member received by the arms and having apertures for holding the said outwardly directed ends; means frictionally held by the arms for restraining said outwardly directed ends; a barrel for receiving and guiding a, pencil; said receptacle having an external spherical surface; a coupling member having an interior spherical surface cooperating with said external surface and carried by the barrel; and means for limiting the relative movement of the receptacle and the barrel.

13. In a pencil sharpener: a barrel for receiving and guiding a, pencil; said barrel having an external thread at one end as well as a plurality of angularly spaced projections extending beyond the body of the barrel; a receptacle having a recess; a plurality of sharpener elements having inwardly directed converging ends disposed in the recess; said receptacle having arms extending toward the diverging ends of the elements; means for holding the diverging ends detachably supported by said arms; means detachably engaged by the arms for restraining the diverging ends against longitudinal movement; the projections of the barrel being engaged between the arms; said receptacle having an exterior spherical surface; and a coupling threaded on the barrel having an inner spherical surface cooperating with the spherical surface of the receptacle; said projections and said arms permitting limited movement between the receptacle and the barrel.

14. In a pencil sharpener: a receptacle having a base with a central aperture therethrough, said aperture having an intermediate shoulder; a ball disposed on the shoulder; a plurality of cutting elements each having a cutting edge extending into said aperture and resting on the ball; said cutting elements diverging outwardly of the aperture; said receptacle having a plurality of angularly spaced arms extending around the elements; a disc having projections entering between adjacent arms and gripped thereby, having apertures holding the diverging ends of the cutting elements; said ends and said disc apertures being non-circular to restrain the elements against rotation; said arms having inner surfaces diverging toward said disc; and a conical washer having its outer edge gripped by said diverging surfaces and having its inner edge overlying said diverging ends of the cutting elements.

15. In a pencil sharpener: a pencil receiver; a plurality of sharpening members, each member being in the form of a bar of uniform cross section, with a plurality of cutting edges; and a support for the members, and carried by the receiver; said support having provisions for holding said members in converging relation with respect to an axis, and so that not more than three of the edges perform a cutting operation, and so that the angular spacing between the edges about the axis is unequal.

HOWARD I-I. EWALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 338,904 Worn Mar. 30, 1886 1,780,371 Benczalski Nov. 1, 1930 2,188,130 Baier et al. Jan. 23, 1940 

